A stator assembly for a rotating electrical machine will normally be mounted to an external support frame. The magnetostrictive forces acting on the stator assembly cause modes of vibration in the radial direction (sometimes called “stator electromagnetic forces”) which can result in large forces being transferred into the support frame. These vibrations in turn cause the support frame to emit noise. In many circumstances, it is desirable to minimise the level of noise that is emitted by the stator assembly. For instance, cruise ships may want to travel into environmentally sensitive areas, and environmental research vessels, fisheries research vessels or naval vessels etc. may want to minimise noise at all times.
The amount of vibration transferred into the support structure can be minimised by decoupling the stator assembly from the support structure using springs. However, existing designs of support structure that use springs are often inefficient, complex, expensive to manufacture and difficult to fit.
There is therefore a need for an improved support structure.
Sandwich anti-vibration mounts are well known for industrial applications. For example, they can be located underneath diesel engines or generator sets to provide a resilient suspension. A typical sandwich mount consists of one or more elastomeric layers formed from rubber or polymer located between two rigid end plates. In some cases, a rigid plate is interleaved between adjacent elastomeric layers for increased loading capability. Sandwich mounts can be used either in compression or shear, or a combination of both. U.S. Pat. No. 6,107,705 discloses a support structure for the stator of a rotating electrical machine where the attachment elements that are mounted between attachment points of an external support frame and the stator are sandwich mounts.